1. Field of the Invention
The present invention relates to a scroll pump having a pump head/motor assembly that includes a stationary plate scroll having a stationary scroll blade, an orbiting plate scroll having a scroll blade nested with the stationary scroll blade, and a pump motor having a rotary output coupled to the orbiting plate scroll so as to drive the orbiting scroll blade relative to the stationary scroll blade. In particular, the present invention relates to a scroll pump having a system that reduces the noise and vibration produced by the pump head/motor assembly.
2. Description of the Related Art
A scroll pump is a type of pump that includes a stationary plate scroll having a stationary plate and a spiral stationary scroll blade projecting axially therefrom, and an orbiting plate scroll having an orbiting plate and a spiral orbiting scroll blade projecting axially therefrom. The stationary and orbiting scroll blades are nested with a clearance and predetermined relative angular positioning such that a pocket (or pockets) is delimited by and between the stationary and orbiting scroll blades. The stationary plate scroll is fixed in the pump. The orbiting scroll plate and hence, the orbiting scroll blade, is coupled to an eccentric driving mechanism. The stationary and orbiting plate scrolls and the eccentric drive mechanism may make up what is referred to as a pump head.
The eccentric drive mechanism is, in turn, connected to and driven by a motor of the pump such that the orbiting scroll plate orbits about a longitudinal axis of the pump passing through an axially central portion of the stationary scroll blade. The volume of the pocket(s) delimited by the scroll blades of the pump is varied as the orbiting scroll blade moves relative to the stationary scroll blade. The orbiting motion of the orbiting scroll blade also causes the pocket(s) to move within the pump head assembly such that the pocket(s) is selectively placed in open communication with an inlet and outlet of the scroll pump.
In an example of such a scroll pump, the motion of the orbiting scroll blade relative to the stationary scroll blade causes a pocket sealed off from the outlet of the pump and in open communication with the inlet of the pump to expand. Accordingly, fluid is drawn into the pocket through the inlet. Then the pocket is moved to a position at which it is sealed off from the inlet of the pump and is in open communication with the outlet of the pump, and at the same time the pocket is collapsed. Thus, the fluid in the pocket is compressed and thereby discharged through the outlet of the pump.
In the case of a vacuum-type of scroll pump, the inlet of the pump is connected to a chamber that is to be evacuated. Conversely, in the case of a compressor-type of scroll pump, the outlet of the pump is connected to a chamber that is to be supplied with pressurized fluid by the pump.
In any case, the rotary components of the pump head and motor produce vibrations. These vibrations, in turn, can generate sound waves, i.e., the rotary components can create a significant amount of noise. The vibrations can also be transmitted to other nearby equipment, resulting in reduced performance of that equipment.